Steel 51100-HR (Hot rolled)
Supply condition
AISI/SAE 51100 · ASTM A295
As-rolled bar for forging or re-heat-treatment stock; hard and unsuitable for direct machining.
Values for the HR condition
Other 51100 tempers and conditions
51100 is listed in 7 conditions; see the grade overview at 51100.
Compare all 7 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
AnnealedDefault Annealed (spheroidize annealed bar/tube) | Standard mill-supplied condition for machining, cold forming and subsequent through hardening. | 400 | 640 | 25 | 192 HB | 46 W/m·K |
Normalized (≈870 °C, air cooled) | Used to break up carbide networks in forgings before spheroidize annealing. | 520 | 900 | 12 | 26 HRC | 8 % IACS |
HRThis page Hot rolled | As-rolled bar for forging or re-heat-treatment stock; hard and unsuitable for direct machining. | 550 | 900 | 12 | 27 HRC | 8 % IACS |
Cold drawn | Close-tolerance bright bar and wire for rollers, pins and cold-headed blanks. | 620 | 760 | 10 | 19 HRC | 8 % IACS |
quench + temper 300–400 °C | Tougher tempered condition for shafts, cams and wear parts where shock loading matters more than peak hardness. | 1,400 | 1,600 | 5 | 48 HRC | — |
oil quench + temper 180–230 °C | Slightly softer temper for better dimensional stability and impact tolerance in service to ~200 °C. | 1,700 | 2,050 | 2 | 60 HRC | — |
oil quench + low temper (150–180 °C) | Standard through-hardened bearing condition for maximum rolling-contact fatigue life and wear resistance. | 1,800 | 2,200 | 1 | 62 HRC | 36 W/m·K |
What is 51100-HR?
51100-HR is 51100 supplied in the HR condition — as-rolled bar for forging or re-heat-treatment stock; hard and unsuitable for direct machining. 51100-HR has a yield strength of 550 MPa (79.8 ksi) and a tensile strength of 900 MPa (131 ksi) — stronger than 71% of steel grades. Elongation at break is 12% and the elastic modulus is 205 GPa (29.7 Msi). 51100-HR has a density of 7.81 g/cm³ (0.282 lb/in³), lighter than 84% of steel grades. It melts at 1,415°C (2,579 °F). Annealed is the default condition FabDigit quotes; HR is available on request or by drawing note.
Advantages
- Polishes to a fine finish — 88/100, better than 100% of steel grades
Limitations
- Difficult to weld — 10/100, worse than 99% of steel grades
- Low fracture toughness — 35 MPa·√m (31.9 ksi·√in), worse than 94% of steel grades
- Difficult to machine — 28/100, worse than 91% of steel grades
- Limited ductility — 12%, worse than 84% of steel grades
- Limited formability — 20/100, worse than 80% of steel grades
51100-HR properties
Typical room-temperature values for 51100-HR; 23 are specific to this condition. Other listed values are 51100 reference data and may not represent this condition. Bars are the position among steel grades.
Physical3
51100-HR has a density of 7.81 g/cm³ (0.282 lb/in³), lighter than 84% of steel grades. It melts at 1,415°C (2,579 °F).
Mechanical16
51100-HR has a yield strength of 550 MPa (79.8 ksi) and a tensile strength of 900 MPa (131 ksi) — stronger than 71% of steel grades. Elongation at break is 12% and the elastic modulus is 205 GPa (29.7 Msi).
Thermal6
51100-HR is rated for continuous service to 400°C (752 °F). It conducts heat at 45 W/m·K (26 BTU/hr·ft·°F), better than 66% of steel grades. Thermal expansion is 11.9 µm/m·K (6.61 µin/in·°F).
Electrical3
51100-HR conducts electricity at 8 % IACS, better than 55% of steel grades.
Chemical & Environmental3
Corrosion resistance is not recommended (10/100), worse than 86% of steel grades.
Sustainability4
Producing a kilogram of 51100-HR takes about 34 MJ of energy and emits 2.4 kg of CO₂ — more than 82% of steel grades. Typical recycled content is 25%.
Manufacturability8
51100-HR's machinability is poor (28/100, worse than 91% of steel grades); weldability not recommended (10/100); formability poor (20/100).
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with 51100-HR
Is 51100 easy to machine?
Machine only in the spheroidize-annealed condition (~40 % of AISI 1212) with rigid setups and carbide tooling; hardened parts require grinding, honing or CBN hard turning.
Can 51100 be welded?
Effectively non-weldable in production — ~1 % C causes quench cracking; if repair is unavoidable, preheat 300–400 °C and post-weld temper immediately.
Can 51100 be formed, bent or molded?
Cold heading and upsetting are done spheroidize-annealed; hot forge 1050–1150 °C, finish above 900 °C and slow-cool then re-anneal to avoid carbide networks.
What surface finishes work on 51100?
Harden at 800–840 °C in oil, temper 150–180 °C, then grind and superfinish; protect with oil film, black oxide, manganese phosphate or thin dense chrome since the alloy has no inherent corrosion resistance.
51100 chemical composition (wt %)
Limits by weight percent from the governing specification, written the way the spec states them — a single maximum for impurities, a range for alloying elements, and the base element as balance. Nominal is the typical mid-range value.
| Element | Spec limit (wt %) | Nominal |
|---|---|---|
| CASTM A295 grade 51100 | 0.98 – 1.1 | 1.03 |
| Mn | 0.25 – 0.45 | 0.35 |
| Si | 0.15 – 0.35 | 0.25 |
| Crleaner than 52100 (1.30–1.60 Cr) | 0.9 – 1.15 | 1.02 |
| P | ≤ 0.03 | — |
| S | ≤ 0.02 | — |
| Niresidual max | ≤ 0.25 | — |
| Curesidual max | ≤ 0.3 | — |
| Moresidual max | ≤ 0.1 | — |
| Fe | balance | — |
51100-HR — frequently asked
What is 51100-HR used for?
51100-HR is typically used for small to medium bearing races, precision rollers, bearing balls, cam followers and track rollers, pump and gear shafts requiring high hardness and bushings and thrust washers. In short: lower-Cr 52100 alternative; ASTM A295 bearing grade; hardens 45–64 HRC.
What is the yield strength of 51100-HR?
51100-HR has a typical yield strength of 550 MPa (79.8 ksi) and a tensile strength of 900 MPa (131 ksi) — stronger than 71% of steel grades. Strength varies by condition: see the 7 listed tempers.
Is 51100-HR easy to machine?
Not especially — machinability is rated poor (28/100, worse than 91% of steel grades). Machine only in the spheroidize-annealed condition (~40 % of AISI 1212) with rigid setups and carbide tooling; hardened parts require grinding, honing or CBN hard turning.
Can 51100-HR be welded?
Not readily — weldability is rated not recommended (10/100). Effectively non-weldable in production — ~1 % C causes quench cracking; if repair is unavoidable, preheat 300–400 °C and post-weld temper immediately.
What surface finishes work on 51100-HR?
Harden at 800–840 °C in oil, temper 150–180 °C, then grind and superfinish; protect with oil film, black oxide, manganese phosphate or thin dense chrome since the alloy has no inherent corrosion resistance.
Can 51100-HR be formed, bent or molded?
Cold heading and upsetting are done spheroidize-annealed; hot forge 1050–1150 °C, finish above 900 °C and slow-cool then re-anneal to avoid carbide networks.
What is the maximum service temperature of 51100-HR?
51100-HR is rated for continuous use to about 400°C (752 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
What is the difference between 51100 Annealed and 51100-CD?
Annealed is the default condition — standard mill-supplied condition for machining, cold forming and subsequent through hardening. CD: close-tolerance bright bar and wire for rollers, pins and cold-headed blanks. Yield strength is 400 MPa in Annealed versus 620 MPa in CD.
Sources
- ASTM A295/A295M — High-Carbon Anti-Friction Bearing Steel — ASTM International (2014)
- ASM Handbook Vol. 1: Properties and Selection — Irons, Steels, and High-Performance Alloys — ASM International (1990)
- ASM Handbook Vol. 4: Heat Treating — ASM International (1991)
- Machining Data Handbook / ASM Machining volume — ASM International (1989)
Property data is compiled from published supplier and standards handbooks and normalised for comparison. Nothing on this page is a certification — request mill certs, CoC or material test reports with your order.